One of the present problems with the manufacture of general structural components of the types outlined above is obtaining reasonable strength under stress and extension and repetitions thereof, at an appropriate weight, or at a weight which is acceptable for the component in question. Also, very light components can often be manufactured, but the cost is unacceptably high for the given application.
European patent 438792 discloses a method of making flexible beams and helicopter rotor blades and similar components. In this method, a composite material roving is wound in a figure of eight around a mandrel, the mandrel being rotated so that the roving forms a tubular mesh around the mandrel. Thus, the component is formed as a mesh made of overlapping rovings which are supported upon a mandrel during the forming process.
U.S. Pat. No. 3,367,586 and European patent 284497 disclose filament winding machines broadly similar to that disclosed in European patent 438792, in which a roving is wound in a substantially helical pattern around a mandrel.
European patent 213816 discloses the making of a tube or rod by wrapping a filamentary material impregnated with a matrix material in a first helical layer around a former, second and subsequent helical layers being built up around the inner layers, with each succeeding layer being at a different angle to the immediately preceding and immediately succeeding layers.
In all of the above prior art specifications, it is note worthy that the rovings or yarns or filaments which are used are always wrapped around a mandrel, so that the roving is fully supported during the forming process. Further, the articles that are formed by the above described prior art techniques are formed by a plurality of differently directed layers of windings i.e. the desired shape basically is outlined as a mesh of rovings.
In contrast, the method of the present invention permits the formation of relatively complex shapes without the use of mandrels and provides for the formation of components as solid plates or rods rather than mesh constructions. It follows that the method of the present invention is able to provide for the manufacture of structural components which are very light but exceptionally strong, by a method of manufacture which can readily be automated and which, compared to the prior art methods, is relatively simple and rapid to perform.
A further object of the invention is the provision of such structural components produced by this method. A still further object of the invention is the provision of apparatus for use in the above-described process to produce said structural components.